Mitogen-activated protein kinase
（重定向自Map kinase signaling system）
![X-ray structure of the ERK2 MAP kinase in its active form. Phosphorylated residues are displayed in red. Rendering based on pdb entry 2ERK.](/Images/godic/202501/26/ERK2-phosphorylated4203.png")
![Example for the inner workings of a MAP3 kinase: the activation cycle of mammalian Raf proteins (greatly simplified overview).[6][7]](/Images/godic/202501/26/Raf-activation-cycle-sketch4203.png")
![A simplified overview of MAPK pathways in mammals, organised into three main signaling modules (ERK1/2, JNK/p38 and ERK5).](/Images/godic/202501/26/MAPK-pathway-mammalian4203.png")
![Overview of MAPK pathways in yeast. Non-canonical components of the five known modules (mating, filamentation, hyperosmosis, cell wall integrity, sporulation pathways) are colored in blue.](/Images/godic/202501/26/MAPK-pathway-yeast4203.png")
Mitogen-activated protein kinases (MAPK) are protein kinases that are specific to the amino acids serine, threonine, and tyrosine. MAPKs belong to the CMGC (CDK/MAPK/GSK3/CLK) kinase group.
MAPKs are involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflammatory cytokines. They regulate cell functions including proliferation, gene expression, differentiation, mitosis, cell survival, and apoptosis.